Revert "Fix Object Movement allocation in GC"

This reverts commit 9c54466e299aa91af225bc2d92a3d7755730948f.

We're seeing crashes in Shopify CI after this commit.

4 files changed, 5 insertions, 74 deletions

diff --git a/gc.c b/gc.c
index 174da8195e..a10a2193e4 100644
--- a/gc.c
+++ b/gc.c
@@ -574,7 +574,6 @@ struct RMoved {
     VALUE flags;
     VALUE dummy;
     VALUE destination;
-    shape_id_t original_shape_id;
 };
 
 #define RMOVED(obj) ((struct RMoved *)(obj))
@@ -6082,19 +6081,10 @@ invalidate_moved_plane(rb_objspace_t *objspace, struct heap_page *page, uintptr_
 
                     object = rb_gc_location(forwarding_object);
 
-                    shape_id_t old_shape_id = 0;
-                    if (RB_TYPE_P(object, T_OBJECT)) {
-                        old_shape_id = RMOVED(forwarding_object)->original_shape_id;
-                    }
-
                     gc_move(objspace, object, forwarding_object, GET_HEAP_PAGE(object)->slot_size, page->slot_size);
                     /* forwarding_object is now our actual object, and "object"
                      * is the free slot for the original page */
 
-                    if (old_shape_id) {
-                        ROBJECT_SET_SHAPE_ID(forwarding_object, old_shape_id);
-                    }
-
                     struct heap_page *orig_page = GET_HEAP_PAGE(object);
                     orig_page->free_slots++;
                     heap_page_add_freeobj(objspace, orig_page, object);
@@ -8458,28 +8448,12 @@ gc_compact_move(rb_objspace_t *objspace, rb_heap_t *heap, rb_size_pool_t *size_p
 {
     GC_ASSERT(BUILTIN_TYPE(src) != T_MOVED);
 
-    rb_size_pool_t *dest_pool = gc_compact_destination_pool(objspace, size_pool, src);
-    rb_heap_t *dheap = SIZE_POOL_EDEN_HEAP(dest_pool);
-    rb_shape_t *new_shape = NULL;
-    rb_shape_t *orig_shape = NULL;
+    rb_heap_t *dheap = SIZE_POOL_EDEN_HEAP(gc_compact_destination_pool(objspace, size_pool, src));
 
     if (gc_compact_heap_cursors_met_p(dheap)) {
         return dheap != heap;
     }
 
-    if (RB_TYPE_P(src, T_OBJECT)) {
-        orig_shape = rb_shape_get_shape(src);
-        if (dheap != heap) {
-            rb_shape_t *initial_shape = rb_shape_get_shape_by_id((shape_id_t)((dest_pool - size_pools) + SIZE_POOL_COUNT));
-            new_shape = rb_shape_traverse_from_new_root(initial_shape, orig_shape);
-
-            if (!new_shape) {
-                dest_pool = size_pool;
-                dheap = heap;
-            }
-        }
-    }
-
     while (!try_move(objspace, dheap, dheap->free_pages, src)) {
         struct gc_sweep_context ctx = {
             .page = dheap->sweeping_page,
@@ -8504,15 +8478,6 @@ gc_compact_move(rb_objspace_t *objspace, rb_heap_t *heap, rb_size_pool_t *size_p
             return false;
         }
     }
-
-    if (orig_shape) {
-        if (new_shape) {
-            VALUE dest = rb_gc_location(src);
-            rb_shape_set_shape(dest, new_shape);
-        }
-        RMOVED(src)->original_shape_id = rb_shape_id(orig_shape);
-    }
-
     return true;
 }
 
@@ -10094,6 +10059,10 @@ gc_ref_update_object(rb_objspace_t *objspace, VALUE v)
             xfree(ptr);
         }
         ptr = ROBJECT(v)->as.ary;
+        size_t size_pool_shape_id = size_pool_idx_for_size(embed_size);
+        rb_shape_t * initial_shape = rb_shape_get_shape_by_id((shape_id_t)size_pool_shape_id + SIZE_POOL_COUNT);
+        rb_shape_t * new_shape = rb_shape_rebuild_shape(initial_shape, rb_shape_get_shape(v));
+        rb_shape_set_shape(v, new_shape);
     }
 #endif
 
diff --git a/shape.c b/shape.c
index 6227958d2c..86572f9fde 100644
--- a/shape.c
+++ b/shape.c
@@ -404,39 +404,6 @@ rb_shape_id_offset(void)
 }
 
 rb_shape_t *
-rb_shape_traverse_from_new_root(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
-{
-    RUBY_ASSERT(initial_shape->type == SHAPE_T_OBJECT);
-    rb_shape_t *next_shape = initial_shape;
-
-    if (dest_shape->type != initial_shape->type) {
-        next_shape = rb_shape_traverse_from_new_root(initial_shape, rb_shape_get_parent(dest_shape));
-        if (!next_shape) {
-            return NULL;
-        }
-    }
-
-    switch ((enum shape_type)dest_shape->type) {
-      case SHAPE_IVAR:
-        if (!next_shape->edges) {
-            return NULL;
-        }
-        if (!rb_id_table_lookup(next_shape->edges, dest_shape->edge_name, (VALUE *)&next_shape)) {
-            return NULL;
-        }
-        break;
-      case SHAPE_ROOT:
-      case SHAPE_FROZEN:
-      case SHAPE_CAPACITY_CHANGE:
-      case SHAPE_INITIAL_CAPACITY:
-      case SHAPE_T_OBJECT:
-        break;
-    }
-
-    return next_shape;
-}
-
-rb_shape_t *
 rb_shape_rebuild_shape(rb_shape_t * initial_shape, rb_shape_t * dest_shape)
 {
     rb_shape_t * midway_shape;
diff --git a/shape.h b/shape.h
index 9a7d31c369..ddb870f5e7 100644
--- a/shape.h
+++ b/shape.h
@@ -178,8 +178,6 @@ rb_shape_t * rb_shape_alloc(ID edge_name, rb_shape_t * parent);
 rb_shape_t * rb_shape_alloc_with_size_pool_index(ID edge_name, rb_shape_t * parent, uint8_t size_pool_index);
 rb_shape_t * rb_shape_alloc_with_parent_id(ID edge_name, shape_id_t parent_id);
 
-rb_shape_t *rb_shape_traverse_from_new_root(rb_shape_t *initial_shape, rb_shape_t *orig_shape);
-
 bool rb_shape_set_shape_id(VALUE obj, shape_id_t shape_id);
 
 VALUE rb_obj_debug_shape(VALUE self, VALUE obj);
diff --git a/test/ruby/test_gc_compact.rb b/test/ruby/test_gc_compact.rb
index c5fac64ca4..bae29a3162 100644
--- a/test/ruby/test_gc_compact.rb
+++ b/test/ruby/test_gc_compact.rb
@@ -270,9 +270,6 @@ class TestGCCompact < Test::Unit::TestCase
       ary = OBJ_COUNT.times.map { Foo.new }
       ary.each(&:add_ivars)
 
-      GC.start
-      Foo.new.add_ivars
-
       stats = GC.verify_compaction_references(expand_heap: true, toward: :empty)
 
       assert_operator(stats[:moved_up][:T_OBJECT], :>=, OBJ_COUNT)